The present invention refers to a reactor for carrying out biological reactions by means of biocatalysts, and in particular to a bioreactor of the type having a base which houses an agitator unit, monitor and control devices and is tightly sealable by a lid.
Bioreactors of this type are suitable for batchwise or continuous operation, with the biocatalysts being discharged together with the substrate which is subsequently separated.
Other reactors are known in which the biocatalysts are immobilized on a carrier matrix, e.g. so-called "microcarriers" or form themselves a separate matrix through agglomeration, with the microcarrier or the matrix of biocatalysts being arranged in a cylinder through which substrate flows from below to thereby fluidize the microcarrier or matrix of biocatalysts in form of a fluidized bed. When the substrate flows through the matrix or the microcarrier, the specific weight thereof and the synchronized flow velocity allows the microcarrier or the matrix to remain in the cylinder while the transformed substrate is withdrawn from the upper end and returned to the circulation. The circulation line is connected to a gas exchanger in which the substrate is enriched with oxygen and the formed carbon dioxide is withdrawn. Additionally connected to the circulation line are heating elements, pH measuring elements, oxygen sensors, temperature sensors and a circulation pump. Such designs have the disadvantage that oxygen can be introduced into the substrate only to a degree as can be dissolved therein so that the oxygen concentration within the fluidized bed drops considerably and the oxygen portion of the substrate in the upper area of the fluidized bed is so low as to mar the further reaction.